This invention relates generally to electrostatographic apparatus and, more particularly, to radiant energy apparatus for fixing toner images to substrate material.
In the process of electrostatography, latent electrostatic images are formed on a support member, for example, plain paper with the subsequent rendering of the latent images visible by the application of electroscopic marking particles, commonly referred to as toner.
The toner images can be fixed directly on the support member on which they are formed or they may be transferred to another support member with subsequent fixing of the images thereto.
Fixing of toner images can be accomplished by various methods one of which is by the employment of thermal energy. In order to permanently fix a fused toner image onto a support member by means of thermal energy, it is necessary to elevate the temperature of the toner material to a point at which the constituents of the toner coalesce and become tacky or melt.
This action causes the toner to be absorbed to some extent into the fibers of the paper. Thereafter as the toner cools, solidification of the toner material occurs causing it to be firmly bonded to the support member. In the process of electrostatography, the use of thermal energy for fixing toner images is old and well known.
One approach to thermal fusing of toner images onto a support member is to pass the support with the toner images thereon past a source of radiant energy such that the image bearing side of the support is opposite the source of radiation while the reverse side thereof is moved in contact with a support platen.
Reflectors are normally employed in conjunction with the source of radiant energy to focus the energy on the toner images carried on the support material.
More recently the utilization of a lens in the radiant fuser for improving thermal efficiency has been recognized (i.e. U.S. Pat. No. 3,811,828). The lens is utilized in conjunction with what appears to be a parabolic reflector and is interposed between the source of radiant energy and the toner images to be fused.
Furthermore, the aforementioned patent recognizes that a stationary guide interposed between the source of radiant energy and the images has certain shortcomings, therefore, adverse effects of continued exposure to elevated temperatures and where the stationary guide contacts the toner images the accumulation of excess toner on its surface.
Notwithstanding the fact that the structure disclosed in the aforementioned patent represents an improved radiant fuser system it falls short of being a totally acceptable device for its intended purposes.
Accordingly, the primary object of this invention is to provide an improved radiant fuser device for fixing toner images to substrate material.
A more particular object of this invention is to provide, in a radiant fuser device for fixing toner images to substrate material, a moving lens and guide structure interposed between the energy source and the toner images.
Another object of this invention is to provide a guide structure for a radiant fuser wherein the guide structure is so designed as to minimize the adverse effects of the radiant energy source.
A further object of this invention is to provide a guide structure for a radiant fuser wherein the structure is designed to minimize toner offsetting thereto.
Yet another object of this invention is to provide a radiant fuser device comprising less elements thereby facilitating manufacture and minimizing costs thereof.
Still another object of this invention is to provide a radiant fuser for fixing toner images to substrate material which lends itself to greater design latitude through the employment of a lens and parabolic reflector for focusing energy onto the toner images.